Electric musical instrument.



H. SCUTERUD.

ELECTRIC MUSICAL INSTRUMENT.

APPLICATION FILED MAY29,1914.

1,245,517. Patented Nov. 6,1917.

Z02 eases:

HAROLD SCUTERUD, (2Fv DORCHESTER, MASSACHUSETTS, ASSIGNOR T0 CHORALCELO COMPANY, OF BOSTON, MASSACHUSETTS, A. COEPORATIQN 0F MAINE.

ELECTEIG MUSIGAL INSTRUMENT.

Specification or Letters Patent.

Patented Nov. 6, 1917.

Application filed May 29, 1914. Serial 13o. MLdGQ.

7 '0 all whom 2'17 may concern:

Be it known that I HAROLD Sonrnnno, a subject of the King oi Norway, residing at Dorchester, in the county oi Sufi'olk and State of Massachusetts, have invented certain new and useful Improvements in Electric Musical Instruments, of which the following is a specification.

This invention relates to an improvement in electric musical instruments of that type wherein tuned sonorous bodies are vibrated electromagnetically.

The object of the invention is to provide an instrument of the character above described, having tuned bars, bands or reeds, which produce a loud, clear tone, free from objectionable harmonics when vibrated electromagnetically.

The invention will be readily understood from an inspection of thev accompanying drawing, in which Figure 1 is a central vertical section through an illustrative embodiment of the invention, Fig. 2 is a plan view of the reed and its support, Fig. 3 is a transverse vertical section on the line 3-3 in Fig. 2, Fig. 4 is an end elevation of the parts shown in Fig. 2, and Fig. 5 is a side elevation. I

As illustrated in the drawing, a sonorous body in the form of a band 10, preferably of sheet metal, is mounted upon a stifii frame or support 12, preferably of cast iron. As shown the frame is rectangular and provided with a pair of raised ribs or webs 14, 15, at each end, separated by a space 16, thus forming'a trough at each end of said frame. The ends of the sonorous body 10 are secured to the end portions of the frame 12 by means of screws '18. The body 10 is engaged intermediate its ends by a pair of bars 20, which are clamped against said body by screws or bolts 22, said screws being preferably threaded into the meta at the bottom of the troughs. By manipulating the screws 22, the body 10 is put under tensionto bring the same to the required pitch. The body 10 is preferably provided with elongated slits 24, which, as shown, extend substantially the entire distance between the two inner webs 15, as shown in Fig. 2, that is,-throughout substantially the tree portion of said body, and may in some cases be continued beyond the-free portion of said body. These slots are for the purpose of prevent ing transverse vibration of the sonorous body, thus-eliminating the otnectionable harmonies from the tone emitted when said body is vibrated by the electromagnet, as will be hereinafter explained. Although the slits are shown as continuous, they may be interrupted at the portion carrying the armature or binding plate.

I am aware that vibrators in the nature of buzzers, and in which the vibrating body rapidly makes and breaks electrical con-' tact, therebyalternately completin and interrupting an electric circuit, have %een perforated immediately around the point of contact to overcome the heating incident to sparking and to the hammering edect, which heating tends to produce elongation or expansion of the vibrating member, and hence to alter the sound produced.

ll am further aware that it has been proposed to employ a radially slitted diaphragm, brazed, soldered, or otherwise rigidly secured to a ring or annular'support, concentric with the disk, and positioned to coincide with a nodal line of the diaphragm the purpose being to produce a symmerricai structure, and to counteract the lack of homogeneity in metallic diaphragms incident to the mode of producing metallic sheets.

ll am not aware, however, that it has ever before been proposed to provide a flat vibrating strip or'bar stressed only in the direction of its length, with a longitudinal slit or slits whereby transverse vibration is prevented, and objectionable overtones or partials are eliminated The sonorous body is arranged to be vibrated by an electromagnet 26, comprising in the *present instance a pair of coils mounted upon a yoke 28, which is adjustable by means of a screw 30 passing through a web or bar 32 at the bottom of the frame 12, and threaded through said yoke. The magnet is also adjusted b means of two pairs of screws 34, 35, w 10h are threaded through the bar 32and engage the under sideof the yoke 28, these screwsbeing arranged to adjust the poles of the magnet with respect to armature 36, both as to parallelism and proximity therewith.

The armature 36 extends transversely of the sonorous body 10 on the under side thereof, and a bar or binding plate 38 extends transversely of said body on the opposite or upper side of said bodv, said bar and armature being preferably separated from direct engagement with said body by strips of yielding material 40, such as felt or the like, and held in place by screws 42 which extend through the bar 38, felt strips 40, and into the armature; although the armature and bar may be rigidly attached to said body by welding, soldering, or otherwise.

If desired, the sonorous body may be composed of a series of narrow strips or hands of metal, each secured at its ends to the ends of the frame 12, and having its middle portion secured to the armature, said strips being separated a short distance to prevent physical contact, the spaces between said strips performing the same function as the slits24.

i In some cases the sonorous bodies are made of a single piece of sheet metal which is not slitted, and this sheet of metal is covered with a sheet of non-resonant material 44, such as felt for example, which is glued or otherwise affixed to the sonorous body and may extend substantially the whole length of said body between its clamps, as shown in Fig. 5, and acts to soften the'tone and absorb thehigh or disagreeableharmonies, and also to cause it to damp more quickly.

The metal frame 12 rests preferably upon strips of.relatively thick non-resonant material 46, such as felt, which is mounted upon a suitable support 48, thus preventlng the transmission of vibrations from one frame 12 to another through the support 48, it being understood that there is usually a series of such frames, one for each sonorous body. Suitably supported above the sonorous body 10 and in ali'nement therewith is a resonant tube or chamber 50 which, in the present instance, is open at both ends.

The means for intermittently energizing the electromagnet comprises a pulsation-device having a uniformly'rotated ring or disk 52, having alternate teeth and insulating material engaged by a brush 54, said brush being connected by a wire 56 to one end of the magnet coil 26, and the other end of ,said magnet coil being connected by a wire 58 to a contact-member 60. The contact-member 60 cooperates with a brush 62, carried by a key 64, like the key of a piano, and said brush 62 is connected by a wire 65 to one pole of a current source '66, the other pole of said sourcebeing connected by a wire 67 to a brush 68, and this brush is in engagement with a shaft70, which carries the disk 52. The disk 52 is rotated at a constant speed, which is secured through the agency of a synchronizer 72 similar to that'in use in an instrument known as the choralcelo, and when the key 64 is depressed to cause the brush 62 to engage the contact-member 60, pulsatory current is transmitted to the electromagnet 26, the frequency of said pulsetions being dependent upon the speed of rotation of the disk 52 and the number of teeth thereon. The bars 20 are clamped against the body 1 0, and the screws 22 are turned until the body emits the desired tone, which indicates that it has been brought to the desired pitch,'the impulses of the magnet being correctly timed to correspond to the number of vibrations of the desired tone.

The general construction and mode of operation of the choralcelo above referred to is set forth and illustrated more or less fully in Letters Patent No. 1098983, granted to M. L. Severy and G. B. Sinclair, and'dated June 2nd, 1914. As stated, the device of the present application is intended for use in such an instrument, and as a substitute for the tuned sonorous bodies thereof, a series of said devices being provided, tuned to the musical scale, and brought into action in the same manner essentially as are the tuned sonorous bodies of said patent.

It is obvious that when the sonorous body 10 is of a material other than metal, the tensioning means may be altered to fit the needs of the particular material, as for example, when the sonorous body is of wood, the tensioning means would preferably be such as to produce a longitudinal strain without the transverse flexure given to the metal sonorous body as shown in Fig. 2. Any means of suitably tensioning sonorous bodies of this type comes well within the province of my invention, and I do not limit myself to the one shown.

I do not confine myself to the particular kind or shape of resonator used, as the character of the tone desired in various cases will dictate resonators of a wide variety of shapes and styles, some being closed at one end, some open at both ends, some partly closed, and so on. The office of the resonator is, as in the case of all true or technical resonators, the elimination of extraneous sounds, overtones, and the like, and the clear bringing out of the one tone or note to which the vibrating body is tuned. In other words, the resonator here contemplated is not a mere sounding-board, horn, or device intended to take up and amplify composite sounds or a plurality of distinct notes or sounds, but ratherto segregate and make clear one particular note or sound.

What I claim is 1. A sound-producing device comprising a flat, broadly extended, tuned sonorous body; a support for said'body coextensive with its width and to which its ends are secured; means for longitudinally stressing said body uniformly throughout its width; and means for vibrating said body.

2. A sound-producing device comprisin a. flat, broadly extended. tuned sonorous bo y; a support for said body coextensive with its width and to which its ends are secured; means for longitudinally stressing said body uniformly throughout its Width; means for vibrating said body; and a resonator in proximity to said sonorous body, said resonator serving to damp or suppress extraneous sounds and to intensify the note to which the body is tuned.

3. A sound-producing device comprising in combination, a support having at either end two separated ribs; a sheet metal member passing over said ribs and secured at its ends to said support; bars overlying the sheet metal member between the ribs of the respective pairs; means for drawing said bars inward between the ribs and thereby longitudinally tensloning the sheet metal member uniformly throughout its width, to bring the same to a predetermined pitch; and electromagnetic means for vibrating said I member.

4. "A sound-producing device comprising in combination, a support; a tuned sheet metal sonorous body having its ends secured to said support, provided with longitudinal slits eX- tending throughout substantially the tree portion of said body, whereby lateral or edgewise vibration of the body is prevented or lessened and undesirable overtones are suppressed or minimized; and electromagnetic means for eli'ecting vibration of said body.

5. A sound-producing device comprising in combination, a resonator; a supporting frame in proximity to said resonator, having near its end a pair of separated ribs transverse to the major axis of the frame; a tuned sheet metal sonorous body extending lengthwise of said frame, resting upon said ribs, and secured at its extremities to the frame but free at its sides; and means acting face-Wise upon said sonorous body intermediate said ribs, and adjustable to vary the tension of said sonorous body without changing the plane of its free or vibrating portion, or varying its relation to the resonator.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HARULD SCUTERU D.

Witnesses EDWARD S. CROCKETT, CARL M. lvERsEN. 

